Residential

17 Must Haves When Building An Energy Efficient Home

Why build an energy-efficient home? The answer is convincing. 

An energy-efficient home saves money by reducing energy use, provides a higher level of comfort to its occupants and increases the resale value of the house. Energy-efficient homes also fight against increas­ing green­house gases and global warming. Negative impacts of global warming include rising sea levels due to growing rates of glacial melting, more acidic oceans due to climbing carbon dioxide levels, and more frequent and severe weather events. For­tu­nate­ly, recent tech­no­log­i­cal advance­ments in building materials and con­struc­tion tech­niques make the process of building an energy-efficient home less challenging.

Energy-Efficient Homes Must-Haves

New home builders have many decisions to make when building an energy-efficient home; however, most energy-efficient homes have several things in common. An energy-efficient home has a tightly sealed thermal envelope, con­trolled ven­ti­la­tion, high-effi­cien­cy heating and cooling systems, and energy-efficient doors, windows, appli­ances, and home elec­tron­ics. The ultimate goal of an energy-efficient home is to achieve net zero energy use and create a com­fort­able home with high indoor envi­ron­men­tal quality.

1. A Whole-Building System Approach for Designing an Energy-Efficient Home

The whole-building system approach treats a home as one energy system in which each part affects the per­for­mance of the whole-house. The whole-building system approach makes efficient use of water, elec­tric­i­ty and other natural resources and strives to minimize waste and materials. It also ensures that all the building pro­fes­sion­als are informed and under­stand every aspects that affect energy use in the home. The goal of the whole-building system approach is to create a home with lower utility and main­te­nance costs, improved dura­bil­i­ty and comfort, and a healthy and safe indoor envi­ron­ment. Archi­tects, con­trac­tors, and home­own­ers agree that designing an energy-efficient home requires a whole-building system approach.

2. Site and Room Orientation of an Energy-Efficient Home

Proper site ori­en­ta­tion (passive solar design) of a home is essential for taking advantage of the sun’s energy. Specif­i­cal­ly, in the Northern Hemi­sphere homes should be oriented north-south. The north-south ori­en­ta­tion minimizes direct sunlight during the summer (which lessens cooling demands) while max­i­miz­ing sunlight during the winter (which lessons heating demands).

Room ori­en­ta­tion is also an important design con­sid­er­a­tion of an energy-efficient home.

  • South facing rooms have good sun most of the day and are ideal for the main living spaces like living, family, and dining rooms.
  • East facing rooms have good sun during the morning and are cool in the late afternoon, which is great for kitchens and bedrooms.
  • West facing rooms get the late afternoon sun, which can be a problem for kitchens and bedrooms.
  • North facing rooms have low levels of sunlight and are best suited for service areas such as garages, laundries and bathrooms.

3. Thermal Mass Materials of an Energy-Efficient Home

High thermal mass materials are an important design element of an energy-efficient home and typically used in walls and slab foun­da­tions. Thermal mass is the potential of a material to absorb and store heat energy. High thermal mass materials help stabilize tem­per­a­ture shifts within a home by slowing the rate of heat transfer. For example, at night an insulated concrete wall and floor will absorb the cool air and store it within its mass. During the day, if the walls and floors are shaded, they will stay cool and so will the interior of the home. In the winter, during daylight, the concrete walls and floors absorbs the sun’s heat energy. During the night, the heat then slowly spreads through the wall and floor (con­duc­tiv­i­ty) and releases into the home. Water, stone, brick, and concrete are examples of materials with high thermal mass. Steel, wood, and carpeting are examples of materials with low thermal mass and should be avoided as part of an energy-efficient home design.

4. Continuous Insulation of an Energy-Efficient Home

An essential design component of an energy-efficient home is con­tin­u­ous insu­la­tion (CI). In fact, the ASHRAE 90.1 and the Inter­na­tion­al Energy Con­ser­va­tion Code (2015 IECC) require con­tin­u­ous insu­la­tion, which is defined by the ASHRAE Standard 90.12013 as insu­la­tion that is uncom­pressed and con­tin­u­ous across all struc­tur­al members without thermal bridges other than fasteners and service openings. A thermal bridge is a section of a wall assembly that allows heat and energy to flow through it at a higher rate than the sur­round­ing area and reduces the effective R‑value1 of the wall assembly. The purpose of CI is to stop thermal bridging, increase the effective R‑value\ and eliminate con­den­sa­tion. Con­tin­u­ous insu­la­tion stops air leakage (thermal bridging) in a home and saves home­own­ers money and energy by reducing mechan­i­cal ven­ti­la­tion costs and heating and cooling expenses.

5. Air and Moisture Barrier of an Energy-Efficient Home

Pre­vent­ing air and moisture infil­tra­tion to the interior of a house is essential to the design of an energy-efficient home. Air tightness of a home is a critical factor in elim­i­nat­ing thermal bridges. Moisture resis­tance is crucial to pre­vent­ing rot and the growth of mold and mildew, which can sig­nif­i­cant­ly degrade the indoor envi­ron­men­tal quality of a home. To minimize air and moisture infil­tra­tion within a home, an air and moisture barrier, along with con­tin­u­ous insu­la­tion, is imper­a­tive to an energy-efficient home design.

6. Bautex Wall System — Best Practice Towards an Energy-Efficient Home Design

Bautex Wall System is a high thermal mass product that provides con­tin­u­ous insu­la­tion and minimizes air and moisture infil­tra­tion. The Bautex insulated concrete blocks provide an R‑14 con­tin­u­ous insu­la­tion that meets, if not surpasses, the codes and standards of the (ASHRAE 90.1) Code (2015 IECC). Also, appli­ca­tion of the Bautex AMB 20 air and moisture barrier to the Bautex Block wall creates a moisture resistant, airtight home that elim­i­nates thermal bridges and condensation.

In addition, the Bautex Wall System is noise reducing, easy to install, and disaster-resistant and has an ASTM E119 fire rating of four hours with ASTM E84 values for flame speed of zero and smoke devel­op­ment of twenty.

7. Cool Roofs of an Energy Efficient Home

A cool roof of an energy-efficient home protects against solar heat gain and keeps the house and attic space cool. Asphalt shingles, a tra­di­tion­al roofing material, has a high thermal mass and will absorb the sun’s heat, which will transfer to the inside of a home. Typically, a cool roof is made of low thermal mass materials like tiles, slate, or clay that are reflec­tive or have light-colored pigments that reflect the sunlight. A wonderful cool roof option for homes with flat rooftops and limited green space, is a green roof. Green roofs include anything from simple plant cover to a working garden. Cool roofs improve indoor comfort and reduce energy bills. They can also extend the roof’s service life.

8. Insulated and Waterproof Slab Foundation of an Energy-Efficient Home

Slab foun­da­tions are most effective way to separate an energy-efficient home from the ground; saving time, money, and materials. Concrete slabs, along with a con­tin­u­ous layer of rigid foam insu­la­tion under the slab, are perfect for an energy-efficient home design. The high thermal mass of concrete holds radiant energy and keeps a home warm and dry inside. Also, an acid-etched or dyed concrete slab is a very attrac­tive finished floor.

9. The Heating and Cooling System of an Energy-Efficient Home

A home’s heating and cooling system accounts for 48 percent of a home’s energy use. The design of an energy-efficient home should consider high-effi­cien­cy heating and cooling systems that use less energy. For example, the most efficient HVAC system is 95 percent efficient; meaning 5 percent of the energy produced is lost. It is imper­a­tive that HVAC pro­fes­sion­als install the systems in accor­dance with ENERGY STAR homes. Improper instal­la­tion of an HVAC lessens the effi­cien­cy of a system by up to 30 percent. VRF and variable speed HVAC systems are some of the most efficient systems available.

10. Ventilation of an Energy-Efficient Home

Con­trol­ling ven­ti­la­tion of an energy-efficient home is critical because the air-tightness of an energy-efficient home may trap pol­lu­tants (like radon, formalde­hyde, and volatile organic compounds). It is essential for an energy-efficient home to install an energy recovery ven­ti­la­tion system. An energy recovery ven­ti­la­tion system controls ven­ti­la­tion and minimizes energy loss by trans­fer­ring energy from con­di­tioned air going out to fresh incoming air. Other useful methods of ven­ti­la­tion for an energy-efficient home are spot ven­ti­la­tion, such as exhaust fans in the kitchen and bathrooms, along with natural ven­ti­la­tion.

11. Glazing System of an Energy-Efficient Home

The windows, skylights and doors of an energy efficient home provide light, warmth, ven­ti­la­tion, along with energy and cost savings. Design of an energy-efficient home should include energy efficient windows, skylights, and doors appro­pri­ate to the home’s climate zone. Also, in the northern hemi­sphere, major glazing areas should face south to take advantage of the sun’s energy in winter months when the sun is low. For warmer climates, limit south facing windows. If windows face south, install shading devices can prevents excessive heat gain during the hot, summer months.

12. Energy-Efficient Appliances

Design of an energy-efficient home includes energy-efficient appli­ances: washer and dryer, refrig­er­a­tor, dish­wash­er, microwave, dehu­mid­i­fi­er, freezer, etc. Energy-efficient appli­ances reduce a home’s energy use, emit less air pollution and increase the resale value of a home. Selecting ENERGY STAR appli­ances ensure the product saves energy and money and protects the environment.

13. Energy-Efficient Home Electronics

The average home owns 24 elec­tron­ic products, which are respon­si­ble for 12 percent of a home’s elec­tric­i­ty use. In addition in 2015, 24 percent of employed people did some or all of their work at home and require home office equipment. The design of an energy-efficient home must include selection of ENERGY STAR®-labeled office equipment and elec­tron­ics.

14. Lighting of an Energy-Efficient Home

Lighting con­tributes up to 15% of a home’s annual elec­tric­i­ty costs and is a crucial design con­sid­er­a­tion of an energy-efficient home. Controls such as timers, pho­to­cells that turn lights off when not in use and dimmers can save money and energy. Examples of energy-efficient lighting include light-emitting diodes (LEDs), compact flu­o­res­cent lamps (CFLs), and halogen incandescent.

  • Light emitting diodes (LEDs) bulbs contain semi­con­duc­tors diodes that convert elec­tric­i­ty into light. LEDs are often used in recessed fixtures, and small track lights, desk lamps, kitchen, under cabinet lighting, and outdoors. LEDs are about 90 percent more efficient than incan­des­cent light bulbs; however they are expensive, ranging from about $10 to $40. LEDs are the longest lasting energy-efficient bulb. LEDs last 50 times longer than a incan­des­cent, 20 – 25 times longer than a halogen, and 8 – 10 times longer than a CFL.
  • Compact flu­o­res­cent lamps are compact flu­o­res­cent light bulbs often used in recessed or can lighting. They cost between $1.25 and $2.50 for a 60-watt-equiv­a­lent bulb. The CFL bulb burns cool and uses much less energy than a tra­di­tion­al incan­des­cent bulb. However, the cons of the CFL is it may take a minute or more to reach full bright­ness and CFLs contain a small amount of mercury, which makes recycling difficult.
  • Halogen incan­des­cents have a capsule inside that holds gas around a filament to increase bulb effi­cien­cy. They are are similar to tra­di­tion­al incan­des­cent bulbs, but use less elec­tric­i­ty. Halogen are the least expensive energy-efficient lighting option at less than $1 each; however, they do not have the longevity of LED and some of CFL bulbs.

15. Water Heating of an Energy-Efficient Home

Water heating accounts for 15 percent of energy costs and is one of the largest energy expenses in a home. For­tu­nate­ly, there are several high-effi­cien­cy water heater options that can save energy and money: tankless water heater, high-effi­cien­cy water heater, high-effi­cien­cy heat pump water heater, and high-effi­cien­cy solar water heater.

16. Energy-Efficient Home Design Includes Smart Home Devices

Including smarthome products in the design of an energy-efficient home is a con­ve­nient option for a homeowner that saves money and energy and makes a home safer. Examples of smart home products include pro­gram­ma­ble ther­mostats, occupancy or motion sensors, CO2 and other air quality alarms.

17. Renewable Energy Sources of an Energy-Efficient Home

The design of an energy-efficient home should strive to create as much energy as it uses by installing renewable energy measures: for example, solar pho­to­volta­ic (PV) panels, wind system, small hybrid” electric system, or micro­hy­dropow­er. Renewable energy sources can reduce or com­plete­ly eliminate a home’s utility bills and may even have tax incen­tives.

The ultimate goal of an energy-efficient home is to achieve net zero energy use. The design should also strive to meet the Energy Star require­ments for sus­tain­abil­i­ty, the Lead­er­ship in Energy and Envi­ron­men­tal Design (LEED) standards, and the Inter­na­tion­al Green Con­struc­tion Code (IgCC). Achieving these standards and require­ments will create an energy-efficient home that saves money and energy, creates a high degree of comfort for the occupants, and ulti­mate­ly increase the resale value of the house. Visit Bautex Wall System for more infor­ma­tion on must have elements for designing an energy-efficient home.

A build­ing’s wall assembly resis­tance to this flow is measured by its effective R‑value. The effective R‑value includes all the materials used in its con­struc­tion: the studs, siding, drywall, fiber­glass batts, plywood or OSB sheathing, water control plane. The higher the R‑value, the less the con­duc­tiv­i­ties of the wall assembly.